Conventionally, there is a pre-crash safety (PCS) system for reducing or preventing damage due to collision with an own vehicle and objects such as other vehicles, pedestrians, and road structures located ahead of the own vehicle in the travel direction thereof. In the PCS system, time to collision (TTC), which is estimated time for the own vehicle to collide with an object, is calculated on the basis of the relative distance between the own vehicle and the object and the relative speed or the relative acceleration between the own vehicle and the object. Subsequently, on the basis of the calculated time to collision, the PCS system alerts the driver of the own vehicle of an approach by a warning device, etc., or actuates the braking device of the own vehicle, for example.
Examples of the PCS system include a vehicle control device disclosed in Patent Literature (PTL) 1. The vehicle control device disclosed in PTL 1 detects the location of an object by a radar device and determines, using a motion vector of the object based on the result of the detection, whether or not an own vehicle is likely to collide with the object.